Electrical isolation barriers are typically used to electrically isolate one electrical system from another electrical system. For example a transformer used to step down a high voltage on a power line to a lower voltage used in homes contains an isolation barrier. In another example, an isolation transformer may be used to reduce high frequency noise often found at the power outlets of homes. The isolation transformer acts as a low-pass filter to remove high frequency noise.
Another type of electrical isolation barrier often used is optical isolation. Optical isolation uses light to send a signal from one electrical system to another electrical system while electrically isolating one electrical system from the other electrical system. For example, an LED (light emitting diode) may be used to transmit a signal from input circuitry through a fiber optic cable to a photo-detector. Often, a pulse train of light is used to represent the signal from the input circuitry. When the photo-detector receives the pulse train from the fiber optic cable, an output circuit reconstructs the pulse train into the original signal. An optoisolator may use a similar structure but with optical fiber replaced by a thin dielectric sheet.
Optical isolation systems often use more power than a magnetic induction isolation system. In addition, optical isolation systems are often slower than a magnetic induction system. Higher power consumption in an optical isolation system is due in part to the small number of photoelectrons generated in a photo-detector compared to the large number of photons generated in an LED.
A coil transducer formed as part of one or more substrates may be used in conjunction with a magnetic induction isolation system to reduce power and improve the speed of an electrical isolation barrier. A coil transducer may be, for example, a transformer. A material used to fabricate a substrate containing a coil transducer includes polyimide. A polyimide substrate containing a coil transducer may be larger than a silicon substrate containing a coil transducer. However, the electrical properties of a polyimide substrate containing a coil transducer help improve signal throughput and high voltage holdoff. In addition, a polyimide substrate containing a coil transducer is usually cheaper to produce than a silicon substrate containing a coil transducer.